Energy storages (e.g., rechargeable batteries) can be found in a plurality of devices, such as in mobile systems, electric vehicles, etc. Mobile systems use, for example, electrical energy storage cells connected in series. The significance and number of mobile systems, such as so-called smartphones, tablet computers, notebooks, hybrid/electric vehicles, which become available on the market is increasing year after year. There is a constantly increasing demand for electrical storage means, as electronics play an ever greater role in such mobile systems. In recent years, given the economic and ecological requirements, the automotive industry, for example, came under pressure to introduce hybrid motor vehicles which combine two energy sources, wherein one of the energy sources provides electrical energy. Electrical energy is generally stored in chemical form, such as using battery cells, accumulator cells or capacitor cells. In order to achieve the high voltages and high powers required in motor vehicles with electric drives, several such cells, such as four to more than 100 cells, are connected in series, thus generating a stack of cells. A main challenge of the cells connected in series and/or in parallel is the reliability of the entire stack and the reorganization of the stack in the event of one cell error. It is currently the case that, in the event of a failure of one cell in the stack, the entire system is no longer able to operate, even though the stack as such still comprises a sufficient number of intact cells to enable the system to operate. If the system is a purely electric vehicle—but also in the case of most hybrid vehicles—such a cell error usually results in a complete system failure.
For a reliable operation of electric vehicles, battery management systems are used. Alongside the monitoring of the charging state and “health” of the battery cells, it may be the task of the battery management system to arrange for the battery cells to be balanced. In the event of a single defective (discharged) cell, the entire battery pack may fail. Therefore, it is desirable that such cells are short-circuited using a bridging element connected in parallel and are thus bridged. Here, bridging a healthy/charged cell should be avoided as, in this state, the short-circuited cell may trigger a great temperature rise due to self-discharge.
There is a demand for providing an improved concept for bridging an electrical energy storage which allows to increase reliability and/or operational safety of energy supply systems, and/or to reduce the costs.